Composition of matter



Patented Nov. 2, 1943 UNITED STATES PATENT OFFICE COMPOSITION OF MATTERAlbert L. Flenner, Wilmington, DeL, and Bernard M. Sturgis, Pitman, N.J., assignors to 1 L du Pont de Nemours & Company, Wilmington, DeL, acorporation of Delaware No Drawing. Application January 17, 1942, SerialNo. 427,168

6 Claims.

This invention relates to compositions of matter, and more particularlyto mixtures of tetraethylthiuram monosulfide with a minor amount oftetraethylthiuram disulfide and to aqueous emulsions the dispersoid ofwhich contains this mixture.

Tetraethylthiuram monosulfide is known to have value for variouspurposes in pest control, as more particularly set out in AustralianPatent 8,103 /32, British Patent 426,051, and U. S. Patents 1,972,961,2,205,232, 2,206,520 and 2,227,496. A

preferred manner of applying this compound, as

paratively low temperatures and that when incorporated in the dispersoidof an aqueous emulsion that the emulsion is stable at relatively lowtemperatures.

The mixtures of our invention may be obtained in any suitable manner assimply by mixing the two ingredients, but it is more convenient, in viewof the fact that the monosulfide is commonly prepared by desulfurizationof the disulfide, to obtain the mixtures by desulfurization of thedisulfide with a deficiency of desulfurizing agent. Thus the mixtures ofour invention may be obtained by desulfurizing tetraethylthiuramdisulfide with sodium or potassium cyanide used in an amountinsufiicient completely to desulfurize the disulfide. Our invention isparticularly useful in emulsions of the character described in U. S.Patent 2,206,520 in which the tetraethylthiuram monosulfide is dissolvedin an equal quantity of cocoanut oil and the resulting solutionemulsified with a substantially equal quantity of a casein-trisodiumphosphate emulsifier solution composed of four parts trisodium phosphatedodecahydrate, 12 parts of casein and 150 parts of water, with orwithout about 2 parts of sodium decyl sulfate to liquefy the emulsion.

The data given in the following table illustrate the eifect of varyingamounts of the disulfide on the stability of such an emulsion at lowtemperature.

Table I Extent of crystal formation after storage at 37 F. for- Per centof disulfide 24hrs. l 48hrs. l 72 his. I 96 hrs.'

EXP. A

EXP. B

EXP. 0

Normal NaCN nvy 10% deficiency None"..-

From the above data the superior stability of the emulsion containing10% of the disulfide is evident. This makes it possible to prepare aconcentrated emulsion suitable for transportation 1 which issufliciently stable to withstand adverse temperature conditions.

While we have described our invention with reference to a particularemulsion it will be understood that the invention is not limitedthereto. The eifect of the disulfide is that of a pourpoint depressant.It affects the monosulfide to make it fluid and pourable at relative lowtemperatures. It prevents crystallization at low temperature. Theinvention accordingly is useful in connection with any emulsion and isuseful, moreover, wherever a fluid product, whether emulsion or not, isdesired which is relatively stable against low temperatures.

The efiect of the disulfide as a pour-point depressant on themonosulfide is illustrated in the following table:

The several embodiments of our invention illustrated above are given byway of illustration and not by'way of limitation, and it is to beunderstood that variation may be made without departing from the spiritof the invention as long as the pour-point of tetraethylthiurammonosulfide is lowered by including therein a minor amount oftetraethylthiuram disulfide. In most applications we prefer to employmore than 5 per cent of the disulfide, although in some cases as littleas 1 per cent exhibits the general characteristics of the invention. Theupper limit is determined in a like manner by the fluidity of theproducts and preferably is not more than per cent of the disulfide butsuitably may range up to about 25 per cent..

While we have disclosed solubilized casein as the emulsifying agent, itwill be understood that other protective colloids may be substitutedtherefor. Likewise, other wetting agents may be substituted for thesodium salt of the higher sulfated alcohols, or these materials may beomitted entirely. The cocoanut oil may be replaced by other oils whichmay or may not be solvents for the thiuram sulfide and in some cases theoil may be omitted. Other solvents may be employed.

We claim:

1. A composition or matter consisting in an aqueous .emulsion thedisperse phase of which contains tetraethylthiuram inonosulfide inadmixture with a minor amount of tetraethylthiuram disulflde sufficientto reduce the pourpoint of the tetraethylthiuram monosulfide.

2. A composition of matter consisting in an aqueous emulsion thedisperse phase of which contains tetraethylthiuram monosulfide and fromabout 5 to about 25 parts of tetraethyl thiuram dlsulfide for everyparts of the monosulfide.

3. A mixture consisting in tetraethyl thiuram monosulfide and a minoramount of tetraethylthiuram disulfide sufficient to reduce the'pourpointof the tetraethylthiuram monosulfide.

4. A mixture consisting in tetraethylthiuram monosulfide and from about5 to about 25 per cent tetraethylthiuram disulfide. i

5. A composition of matter consisting in an aqueous emulsion thedisperse phase of which contains tetraethylthiuram monosulfide and about10 parts of tetraethylthiuram disulfide for every 100 parts of themonosulfide.

6. A mixture consisting in tetraethylthiuram monosulfide and about 10per cent tetraethylthiuram disulflde.

ALBERT L. FLENNER. BERNARD M. STURGIS.

